(1) Field of the Invention:
The present invention relates generally to an information selection and transfer system, and more particularly, to a data transfer unit arranged between a data memory and a central operation processing unit, provided for an electronic control system for controlling a vehicle such as a motor car.
(2) Description of the Prior Art:
Generally speaking, in various kinds of information selection and transfer systems, when the amount of data to be transferred is not so large, the transfer of information can be performed exactly by directly connecting to each other an information supplying unit such as a data memory and an information processing unit such as a central operation processing apparatus.
When the amount of data to be transferred is extremely large, however, it is required to control the state of transfer of information. Thus, a switching over unit consisting of plural switching elements is connected between the information supplying unit and the information processing unit, and further a switching-over commander is provided for controlling the changing-over of those switching elements, to facilitate the selection and the transfer of desired information between the information supplying unit and the information processing unit.
However, in a conventional information transfer system, in order to perform the selection and transfer of desired information, in response to the demand of the connection between the designated output terminals of the information supplying unit and the designated input terminals of the information processing unit, the combination of those terminals is stored in the switching-over commander for a time, and then the operation for setting the state of switching over ofrespective switching elements in the switching over unit is effected repeatedly with regard to each of the designated output terminals of the information supplying unit by referring to the above stored combination of the terminals. Accordingly, the increase of the amount of information to be transferred causes, the difficulty as the times of repetition of the above operation is increased extremely and a long time duration is required for the above control of switching over.